Well head casing seal

ABSTRACT

Presented is a structure for sealing the opening around a well head to prevent the inadvertent spillage or escape while permitting the recovery and recycling of drilling fluids during the drilling operation.

United States Patent 1 Diaz [54] WELL HEAD CASING SEAL [76] Inventor: Simon J. Dial, 307 Center St.,

McAllen, Tex. 78501 [22] Filed: Nov. 8, 1971 [21] Appl. No.: 196,355

[52] U.S. Cl. ..166/88, 166/96 UNITED STATES PATENTS Weatherwax 1 66/96 Moser 1 Mar. 27, 1973 1,488,211 3/1924 Loeffler ..166/96 2,533,341 12/1950 Shannon... .....166/96 2,988,144 6/1961 Conrad ..166/96 FOREIGN PATENTS OR APPLICATIONS 494,696 7/1953 Canada ..166/96 Primary Examiner.lames A. Leppink Attorney-John J. Leavitt [57] ABSTRACT Presented is a structure for sealing the opening around a well head to prevent the inadvertent spillage or escape while permitting the recovery and recycling of drilling fluids during the drilling operation.

9 Claims, 5 Drawing Figures PATENTEUMARUIQR 3, 722-, 587

SHEET 1 [IF 2 a a INVENTOR- u 3 SIMON J. DIAZ PATENlEnmzmn 3,722,587

sum 2 OF 2 INVENTOR.

SIMON J. DIAZ WELL HEAD CASING SEAL BACKGROUND OF THE INVENTION Most drilling of wells is effected by driving a drill bit downwardly through the earth. Simultaneous with downward movement of the drill bit, a well casing is driven down into the well bore to prevent collapse of the walls thereof. The drill bit must cut through whatever material it encounters, even hard and rocky material, and at the speeds at which drilling is effected, the drill is apt to become overly hot resulting in wear of thebit at an exceptional rate. Accordingly, to preserve the life of the drill bit, various types of drilling fluids are injected into the well bore and caused to circulate about the drill bit so as to carry away soil or rock loosened by the bit, and to effect cooling of the bit. Such drilling fluids are costly, and it is advantageous to be able to recover such drilling fluids for reuse. It is one of the objects of this invention to provide a well head casing seal which enables recovery of such drilling fluids.

In use, drilling fluids are pumped into the well bore under pressure. Unless the well head is sealed, there is a tendency for such drilling fluids to leak or otherwise escape from the well bore. Accordingly, it is still another object of the invention to provide a well head casing seal which prevents the inadvertent escape of the drilling fluids and enables them to be circulated for recovery and reuse.

It has been found that the weight of a well head casing by itself, even if anchored to the ground, does not provide a sufficiently tight seal to prevent the escape of high pressure drilling fluids. Accordingly, it is a still further object of the invention to provide a well head casing seal incorporating an inflatable member which when inflated, exerts both an upward and downwardly directed force tosteady the well head casing and seal the area around the well head.

It is an advantage in driving well casings that the exposed length of the casing be supported over a major portion of its length. Accordingly, it is still another object of the invention to provide a well head casing structure in which means are provided to lend lateral support and stability to a well head casing during its insertion into the well bore.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be apparent from the following description and the drawings. It is to be understood, however, that the invention is not limited by said description and drawings, as it may be embodied in various forms within the scope of the appended claims.

SUMMARY OF THE INVENTION In terms of broad inclusion, the portable well head casing seal of the invention comprises a base member formed by a generally annular main head portion extending transversely with respect to the longitudinal axis of a stationary conductor pipe portion which passes through the inner periphery of the main head portion and is welded thereto. Anchor means are provided interposed between the ground on which the apparatus is supported and the base member to anchor the base member to the ground. Disposed beneath the transversely extending main head portion and the associated surface of the ground, is an inflatable annular seal which when inflated exerts an upward and downward pressure, thus steadying the base member and simultaneously forming a fluid tight seal between the underside of the main head portion and the upper surface of the associated ground. Slidably disposed within the upper end of the stationary conductor pipe portion of the base member is a movable conductor pipe portion adapted to move longitudinally and coaxially within the stationary conductor pipe portion. Such mobility of the movable conductor pipe portion enables adjustment thereof to accommodate different lengths of well casing. Seal means are interposed between the upper end of the stationary conductor pipe portion of the base member and the outer periphery of the movable conductor pipe portion to restrict relative movement therebetween and prevent leakage of drilling fluids therebetween. A drain pipe is provided associated with the upper end of the movable conductor pipe portion to drain off drilling fluids that well up in the well head casing to the height of the drain pipe.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-sectional view, partly in elevation, illustrating the well head casing in position of use.

FIG. 2 is an enlarged fragmentary vertical sectional view taken in the plane indicated by the line 2-2 of FIG. 1.

FIG. 3 is a bottom view of the apparatus taken in the direction indicated by the arrows on line 3-+3.

FIG. 4 is a fragmentary plan view taken in the direction indicated by the arrows on line 4-4.

FIG. 5 is a vertical cross-sectional view, partly in elevation, illustrating another embodiment of the well head casing in position of use.

DESCRIPTION OF THE PREFERRED EMBODIMENT In terms of greater detail, the well head casing. seal of the invention comprises a base member designated generally by the numeral 2, and including a radially extending annular main head portion 3, conveniently formed from a heavy metallic plate the inner periphery 4 of which accommodates the outer periphery 6 of a stationery conductor pipe portion 7. The conductor pipe portion 7 and the inner peripheral portion of the main head portion are preferably welded at 8, and where it is believed necessary, appropriate gussets 9 may be interposed therebetween to lend rigidity to the structure.

The stationary conductor pipe extends below the bottom surface 12 of plate 3 in an extension 13, terminating at 14 as shown. Concentrically disposed about the extension portion 13 is an inner partition 16 which with pipe portion 13 defines an annular cavity 17. In like manner, a second partition 18 is provided concentrically disposed about the partition 16 so as to define therewith an annular cavity 19. Still a third cavity 21 is defined between the partition 18 and an outer wall 22 depending from the peripheral edge portion of plate 3 as shown. Each of the partitions and the outer cylindrical wall 22 are appropriately welded to the underside of plate 3, with access to each of the annular chambers being had from the lower side thereof as viewed in FIG. 3.

To seal the base member to the associated surface of the ground, a depression is preferably formed in the ground having a depth substantially equal to the height of the outer wall 22, and the entire apparatus is lowered into the depression so formed. Preferably the bottom of the depression is leveled so as to provide a flat surface as shown. To render the area around the well head fluid tight, there is provided an annular inflatable seal member 26, preferably formed from an appropriate deformable material such as one of the synthetic or natural rubbers, and having a valve stem 27 attached thereto to effect inflation of the seal member.

The valve stem may be connected by a conduit (not shown) to any appropriate source of high pressure fluid, preferably air, so as to quickly inflate and deflate the seal member. Inflation of the deformable seal member causes the annular seal to conform to the configuration of the chamber 21 (or other chamber) within which it is enclosed, causing the upper surface of the seal to press upwardly against the underside of the plate 3, while the lower side of the seal presses downwardly against the upper surface of the depression within which the apparatus is seated. Since the annular member is trapped within the confines of the annular chamber 21 by side wall 22 and partition 18, it will be apparent that a downwardly directed force will be imposed on the surface of the ground immediately below the seal member. In like manner, an upwardly directed force will be imposed on the underside of the main head portion 3, tending, unless restrained, to raise the entire apparatus out of the depression within which it is seated.

To prevent such-elevation of the apparatus, anchor means in the form of angularly disposed ties 31 are connected between lugs 32 welded to the outer periphery of the upwardly extending stationary pipe portion 7 and appropriate stakes 33 driven into the ground at points radially removed from the well head. It will thus be seen that such ties effectively restrain any upward movement of the apparatus when the inflatable seal is inflated. Such restraint of upward movement of the apparatus will of course cause the amount of pressure exerted on the surface of the ground by the seal member to be correlated to the pounds of pressure to which it is inflated.

With the base member thus anchored and sealed around the well head, a movable conductor pipe 36 is inserted into the upper open end of the stationary conductor pipe portion. The outer diameter of the movable conductor pipe portion is proportioned to slide smoothly within the inner periphery of the stationary conductor pipe portion 7 so as to minimize the possibility of drilling fluids being squeezed between the two pipes and thus be lost on the ground.

To insure against such loss, a deformable generally cylindrical gasket 37 is provided proportioned to snugly slip about the outer periphery of the upper end portion of the stationary conductor pipe, and provided with a radially extending bead portion 38 adapted to snugly abut the outer periphery of the movable inner conductor pipe portion. Fixed to the outer periphery of the conductor pipe 7 are a plurality of radially extending brackets 39 apertured as at 41 to receive upwardly extending draw lugs 42 adapted to pass through appropriate apertures in a bearing plate 43.

The bearing plate is preferably annular in configuration, the inner periphery thereof sliding snugly along the outer periphery of the movable conductor pipe so that when the lug nuts 44 are tightened, the bearing plate 43 moves in relation to the movable conductor pipe and effectively squeezes the deformable bead portion 38 and the gasket 37 tightly against the outer periphery of the conductor pipe 36 and the upper end of the conductor pipe 7. It will, of course, be obvious that other means may be utilized to form a fluid tight seal of such a slide joint.

The deformable seal structure 38-37 will impose a certain amount of restriction to axial displacement of the movable conductor pipe in relation to the surrounding stationary conductor pipe. However, to insure that once adjusted, the movable conductor pipe is retained in fixed position, a plurality of circumferentially spaced cap screws 46 are provided as shown in FIG. 1 to affirmatively lock the two members together.

It will thus be seen that when the drill bit 47 mounted on the end of upwardly extending shaft 48 is rotated,

the cutting elements of the drill bit will loosen the soil into the well head casing formed by the base member and caused to circulate through the bore formed by the drill bit. Such drilling fluids are expensive, and it is advantageous that they be recovered for reuse. Accordingly, the movable conductor pipe portion 36 is provided adjacent its upper end with a drainpipe portion 51, angled downwardly as illustrated, so that when the drilling fluid wells up to the level of the drain pipe, it will flow by gravity into an appropriate container (not shown) where it is recovered for reuse. It will, of course, be apparent that more thanone such drain pipe may be provided, depending upon the volume of drilling fluid to be recovered.

The embodiment illustrated in FIG. 5 is similar to the embodiment illustrated in FIG. 1 and in the interest of brevity, corresponding parts. The embodiment illustrated in FIG. 5 adds to the annular chamber 19 a truncated conical wall section 52 having its large base abutting main end portion 3 and the bottom surface 12 thereof as illustrated. The small base of the conical wall portion 52 is abutted to the free end of annular inner partition 16 as shown. For rigidity, the conical wall 52 is welded at both ends to associated stnicture. The effect of the conical wall 52 is to cause impaction or compression of the soil caught between the inner partition wall 18 and the conical wall 52. This configuration tends to increase the stability of the well head casing when in use.

Having thus described my invention, what is claimed to be novel and sought to be protected by letters 7 patent, is as follows:

I. A well head casing seal comprising:

a. a base member including a main head portion and a stationery conductor pipe portion, said main head portion constituting a platform extending transverse to the longitudinal axis of said stationery conductor pipe portion;

b. anchor means interposed between said base member and the ground on which it is supported to anchor said base member over a well head and prevent lifting thereof in relation to the ground;

. seal means interposed between the underside of said main head portion of the base member and the associated surface of the ground to seal the area around said well head; and

. a movable conductor pipe portion disposed within said stationery conductor pipe portion of the base member and adjustable vertically in relation thereto.

2. The combination according to claim I, in which seal means are interposed between said stationary and movable conductor pipe portions to render the joint therebetween fluid tight and restrict axial displacement of said movable conductor pipe portion in relation to said stationary conductor pipe portion.

3. The combination according to claim 1, in which a flow line is provided communicating the interior of said movable conductor pipe portion with the exterior thereof whereby drilling fluid may be circulated through said conductor pipe portions and a well bore to cool a drill bit working therewithin.

4. The combination according to claim 1, in which auxiliary lock means are provided to fasten said movable conductor pipe portion to said stationery conductor pipe portion.

5. The combination according to claim 1, in which said seal disposed below said main head portion is pneumatically inflatable to exert an upward thrust on said base member and a downward thrust against the associated surface of the ground to seal said well head casing to the ground surrounding the well head.

6. The combination according to claim 1, in which said main head portion is annular and has the inner periphery thereof welded to the outer periphery of the stationery conductor pipe portion adjacent its end, and a plurality of annular walls disposed on one side of the main head portion to selectively receive various sizes of pneumatically inflatable seal members therein.

7. The combination according to claim 1, in which said anchor means includes a plurality of diametrically opposed lugs formed on the stationery conductor pipe portion adjacent its upper end, anchor stakes adapted to be driven into the ground at points radially spaced from said well head, and a plurality of lines interconnecting such anchor stakes and 8. The combination according to claim 2, in which said seal means disposed between the movable conductor pipe portion and said stationary conductor pipe portion includes radially projecting brackets welded to the upper end portion of said stationary conductor pipe portion, a generally cylindrical deformable gasket surrounding the upper end portion of said stationary conductor pipe portion and including a radially projecting bead portion engaging the outer periphery of said movable conductor pipe portion, an annular plate slidably disposed about the outer periphery of said movable conductor pipe portion, and draw means interposed between said annular plate and said radially extending brackets to draw the annular plate tightly against the deformable seal member.

9. The combination according to claim 6, in which a truncated conical wall portion is disposed between a concentric pair of said plurality of inner annular walls." 

1. A well head casing seal comprising: a. a base member including a main head portion and a stationery conductor pipe portion, said main head portion constituting a platform extending transverse to the longitudinal axis of said stationery conductor pipe portion; b. anchor means interposed between said base member and the ground on which it is supported to anchor said base member over a well head and prevent lifting thereof in relation to the ground; c. seal means interposed between the underside of said main head portion of the base member and the associated surface of the ground to seal the area around said well head; and d. a movable conductor pipe portion disposed within said stationery conductor pipe portion of the base member and adjustable vertically in relation thereto.
 2. The combination according to claim 1, in which seal means are interposed between said stationary and movable conductor pipe portions to render the joint therebetween fluid tight and restrict axial displacement of said movable conductor pipe portion in relation to said stationary conductor pipe portion.
 3. The combination according to claim 1, in which a flow line is provided communicating the interior of said movable conductor pipe portion with the exterior thereof whereby drilling fluid may be circulated through said conductor pipe portions and a well bore to cool a drill bit working therewithin.
 4. The combination according to claim 1, in which auxiliary lock means are provided to fasten said movable conductor pipe portion to said stationery conductor pipe portion.
 5. The combination according to claim 1, in which said seal disposed below said main head portion is pneumatically inflatable to exert an upward thrust on said base member and a downward thrust against the associated surface of the ground to seal said well head casing to the ground surrounding the well head.
 6. The combination according to claim 1, in which said main head portion is annular and has the inner periphery thereof welded to the outer periphery of the stationery conductor pipe portion adjacent its end, and a plurality of annular walls disposed on one side of the main head portion to selectively receive various sizes of pneumatically inflatable seal members therein.
 7. The combination according to claim 1, in which said anchor means includes a plurality of diametrically opposed lugs formed on the stationery conductor pipe portion adjacent its upper end, anchor stakes adapted to be driven into the ground at points radially spaced from said well head, and a plUrality of lines interconnecting such anchor stakes and
 8. The combination according to claim 2, in which said seal means disposed between the movable conductor pipe portion and said stationary conductor pipe portion includes radially projecting brackets welded to the upper end portion of said stationary conductor pipe portion, a generally cylindrical deformable gasket surrounding the upper end portion of said stationary conductor pipe portion and including a radially projecting bead portion engaging the outer periphery of said movable conductor pipe portion, an annular plate slidably disposed about the outer periphery of said movable conductor pipe portion, and draw means interposed between said annular plate and said radially extending brackets to draw the annular plate tightly against the deformable seal member.
 9. The combination according to claim 6, in which a truncated conical wall portion is disposed between a concentric pair of said plurality of inner annular walls. 